Apparatus for the automatic transfer of cryogenic liquid from a cold source to a storage vessel



Sept. 21, 1965 J. a. DAMSZ APPARATUS FOR THE AUTOMATIC TRANSFER OF CRYOGENIC LIQUID FROM A GOLD SOURCE TO A STORAGE VESSEL Filed Sept. 19, 1965 INVENTOR JERVZY GDAMSZ AGEN BY Z United States Patent "ice 3,206,938 APPARATUS FOR THE AUTOMATIC TRANSFER OF CRYOGENIC LIQUID FROM A COLD SOURCE TO A STORAGE VESSEL Jerzy G. Damsz, Hastings-on-Hudson, N.Y., assignor to North American Philips Company, Inc., New York, N.Y., a corporation of Delaware Filed Sept. 19, 1963, Ser. No. 309,946 7 Claims. (Cl. 62-55) This invention relates to a system for the automatic transfer of cryogenic liquid from a cold source to a storage vessel. More particularly, the present system transfers cryogenic liquid which is condensed on the cold surface of the cold source to a remotely located dewar container.

It is an object of the present invention to provide the transfer of cryogenic liquid from the cold source to the storage vessel by means of a pressure feed utilizing the vacuum produced by the condensing of gas due to the cold made by the cold source.

Another object of the present invention is the provision of an envelope filled with a clean neutral gas in which is housed both the dewar and a miniature cold gas refrigerator. This arrangement could be used for recondensing and the subsequent cooling of a specimen or object to be cooled.

The above and other features, objects and advantages of the present invention will be fully understood from the following description considered in connection with the accompanying illustrative drawings.

FIG. 1 is a diagrammatic view of the system for transfer of cryogenic liquid from a cold source to a storage vessel in accordance with the teachings of the present invention.

FIG. 2 is a diagrammatic view of \a modification thereof and FIG. 3 is a diagrammatic view of a valve used in the present system.

Referring more particularly to the drawings and especially to FIG. 1 wherein is shown a cryogenic liquid transfer system using as a driving force the vacuum produced by the condensing of gas due to the cold produced at the head of a cold gas refrigerator (not shown). The head 10 is encapsulated in a container 12 which forms the space for the condensed gas. Both the head 10 and the container -12 are housed in a vacuum jacket 13. Two flexible tubes or conduits '14 and 16 are connected in the liquid container 12. Tube 16 has one end affixed to the container 12 and the other end to the vacuum space 18 in the gas container 20, while tube 14 has one end connected to the bottom of the container 12 and the other end comunicating with the dewar or storage vessel 22.

The gas container 20 is provided with a pressure space 24 located above the vacuum space 18, which spaces are separated by a wall 26. A valve 28 connects the vacuum space 18 and the pressure space 24. The valve 28 operates automatically when the pressure difference between the two spaces reaches an established AP. A tube or conduit 30 connects the dewar 22 with the gas container 20, with the latter having a non-return valve 34 at the gas inlet 32.

The present system operates as follows: The system is filled with gas, for example N The cold gas refrigera tor is made operative. The cold produced on the head 10 will condense the N and the pressure will drop in the whole system with the exception of space :24 in the gas container 20. When a small amount of liquid N is collected in the bottom of the container or vacuum jacket 12 encapsulating the cold head 10 of the cold gas refrigerator, the pressure of the gas will become so low 3,206,938 Patented Sept. 21, 1965 that valve 28 will open, that is AP=5 p.s.i.-a. if the system at the start is at atmospheric pressure. At that time, the gas under pressure in space 24 will be forced into the vacuum space 18, through the conduit 16 to the condensing area surrounding the head 10 of the cold gas refrigerator thereby pushing the liquid N in the bottom of the container 12 through the tube '14 to the dewar 22. The dewar 22 will then function as a gas-liquid separator in which the liquid remains in the bottom of the dewar 22 and the gas therein flows to the pressure space 24 through the non-return or one-way valve 34. When pressure in the pressure space 24 and pressure in the vacuum space 18 of the gas container 20 are close to equilibrium the valve 28 will close automatically and the cycle will start from the beg-inning. It should be apparent that the operation of valve 28 will regulate the length of the cycle time and the amount of liquid transferred during each cycle from the space 12 to the dewar 22. The valve 28 should have a delayed action to permit the equalization of pressures in the high pressure space 24 and the vacuum space 18. The gas container 20 is also provided with a safety valve 36 and a valve 40, the latter being connected to the source of gas or the atmosphere. Attached to and communicating with high pressure space 24 is a gauge 38.

The valve 28 is more clearly seen in FIG. 3 and discloses a bellows 42, which if necessary could be spring loaded, and a capillary tube 44 connected to the bellows and communicating with the vacuum space 18. The valve 28 is also provided with an opening 46 as well as the closable valve opening 48. Thus, when the pressure diiference AP between the pressure space 24 and the vacuum space 18 arrives at a predetermined value, the bellows 42 will compress thereby opening the valve opening 48 of valve 28, thus permitting the gas fromthe pressure space to escape through opening 46, valve opening 48 and thence into vacuum space 18'. Thereafter, when the pressure is equalized in the system the bellows 42 expands and the valve 28 closes. The flow through the capillary tube 44 will fill the bellows 42 in a given time which will permit pressure equilibrium in the system. By adjusting the length of the capillary tube 44 the necessary time lag to achieve the correct timing of the valve opening and closing is achieved.

It should be noted that in the present system when due to the cold production produced by a cold gas refrigerator, the gas contained in the system, i.e., dewar 22, container 12 and conduits 14 and 16, will partially liquefy and the pressure in the system will drop. The time required to lower the pressure depends on the volume of the system, the cold production of the refrigerator and the gas used for liquefaction. For example, with a certain volume of the system and a certain amount of cold production of the refrigerator at a LN temperature level and N used for liquefaction there is a time interval between openings of the valve 28 which will produce a required pressure drop during the time when the valve 28 remains open. This produces the transfer of LN from the space 12 to the dewar 22. It should also be noted that the function of the solenoid valve illustrated in FIGURE 2, as well as the timer, replaces the bellows valve and capillary tube shown in FIGURE 1.

FIG. 2 discloses a modification of the system illustrated in FIG. 1. In FIG. 2, the entire system is installed in an envelope 50 which is filed with a clean, neutral gas and which could be used for recondensing and subsequent cooling of a specimen present in the dewar 22. In this construction, the pressure space of gas container 20 is replaced by the envelope 50. Non-return valve 34 is mounted directly on the dewar 22 and the valve 28 on the cold gas refrigerator. If the cold gas refrigerator is installed outside of the envelope, valve 28 will have to be brought inside the envelope 50 and located therein. The solenoid valve 28 and timer permit the equalization of the pressure in the space 50 and inside of the system, the latter including the dewar 22, container 12 and flexible tubes 14 and 16. The interval of time for opening the solenoid valve will be relatively short to permit equalization of pressure and to transfer the liquid in container 12 to dewar 22. The time during which the solenoid valve is closed will be relatively long and will depend upon the cold production of the unit since during this period a suificient amount of liquid will be accumulated in container 12.

While I have shown and described the preferred embodiment of my invention, it will be understood that the latter may be embodied otherwise than as herein specifically illustrated or described and that in the illustrated embodiment certain changes in the details of construction and in the arrangement of parts may be made Without departing from the underlying idea or principle of the invention within the scope of the appended claims.

WhatIclaim is:

1. An automatic liquid transfer system containing gas comprising a cold source, a liquid container operatively connected to said cold source, a gas container divided into two spaces and provided with .a normally-closed valve adapted to communicate with both spaces of said gas container, one space of said gas container being at a pressure and the other space being a vacuum, a storage vessel for said liquid, a first line connecting said cold source liquid container with the vacuum space. of said gas container, a second line connecting said cold source liquid container to said storage vessel, a third line connecting said storage vessel to said gas container, said cold source liquefying said gas, said liquid being transferred from said cold source liquid container to, said storage vessel by means of the pressure drop in the system causing said valve to open and said gas under pressure to force said liquid into said storage vessel through a selected line, and said third line leading the vapors generated from said transferred liquid in the storage vessel to the pressure space in one direction only.

2. An automatic liquid transfer system containing gas comprising a cold source, a liquid container operatively connected to said cold source, a gas container divided into two spaces and provided with a normally-closed valve adapted to communicate with both spaces of said gas container, one space of said gas container being at a pressure and the other space being a vacuum, a storage vessel for said liquid, a first line, connecting said cold source liquid container with the vacuum space of said gas container, a second line connecting said cold source liquid container to said storage vessel, a third line connecting said storage vessel to said gas container, said cold source liquefying said gas, said liquid being transferred from said cold source liquid container to said storage vessel by means of the pressure drop in the system causing said valve to open and said gas under pressure to force saidliquid into said storage vessel through a selected line, and said third line having a one-way valve therein.

3. An automatic liquid transfer system containing gas comprising a cold gas refrigerator provided with a cold head. an enclosure encapsulating said cold head, a gas container divided into two spaces and provided with a normally-closed valve adapted to communicate with both spaces of said gas container and a plurality of conduits connecting the enclosure of the cold head of said cold gas refrigerator to said gas container and storage vessel, one space of said gas container being at a pressure While the other space is at a vacuum, said liquid being transferred from the enclosure to said storage vessel by means of the pressure drop in the system causing said valve to open and said gas under pressure to force said liquid into said storage vessel through a selected conduit, and means for leading the vapors generated from said transferred liquid in the storage vessel to the pressure space in one direction only.

4. An automatic liquid transfer system as claimed in claim 1 wherein said valve includes a bellows and a capillary tube connected thereto and in communication with said vacuum space.

5. An automatic liquid transfer system as claimed in claim 4 wherein the length of said capillary tube determines the amountof time lag for determining the timing of said valve opening and closing.

6. An automatic liquid transfer system containing gas comprising a cold source, a liquid container operatively connected to said cold source, an enclosure for said cold source, a storage vessel for said liquid and a first tube connecting said liquid container to said storage vessel, a timer and valve, said valve being operated by said timer to transfer liquid from said container about said cold source to said storage vessel, and a sealed envelope filled with a neutral gas having said cold source, storage vessel, timer, valve and associated tubes located therein, said valve having a valve inlet" in communication with the interior space of said sealed envelope and said .valve being provided with a'second connected to said cold source liquid container, and means for leading the vapors generated from saidtransferred liquid in said storage vessel to said sealed envelope in one direction only.

7. An automatic liquid transfer system as claimed in claim 6 further comprising -a one-way valve mounted directly on said storage vessel permitting the gas therein to escape into the interior of said envelope.

References Cited by the Examiner UNITED STATES PATENTS 2,756,765 7/56 Agule et al. 62--55 2,836,964 6/58 Roozenaal et al. 626 3,001,379 9/ 51 Fukuzawa et al. 625 14 3,025,680 3/62 De Brosse et a1. 62514 ROBERT A. OLEARY, Primary Examiner. 

1. AN AUTOMATIC LIQUID TRANSFER SYSTEM CONTAINING GAS COMPRISING A COLD SOURCE, A LIQUID CONTAINER OPERATIVELY CONNECTED TO SAID COLD SOURCE, A GAS CONTAINER DIVIDED INTO TWO SPACES AND PROVIDED WITH A NORMALLY-CLOSED VALVE ADAPTED TO COMMUNICATE WITH BOT SPACES OF SAID GAS CONTAINER, ONE SPACE OF SAID GAS CONTAINER BEING AT A PRESSURE AND THE OTHER SPACE BEING A VACUUM, A STORAGE VESSEL FOR SAID LIQUID, A FIRST LINE CONNECTING SAID COLD SOURCE LIQUID CONTAINER WITH THE VACUUM SPACE OF SAID GAS CONTAINER, A SECOND LINE CONNECTING SAID COLD SOURCE LIQUID CONTAINER TO SAID STORAGE VESSEL, A THIRD LINE CONNECTING SAID STORAGE VESSEL TO SAID GAS CONTAINER, SAID COLD SOURCE LIQUEFYING SAID GAS, CONTAINER, SAID FERRED FROM SAID COLD SOURCE LIQUID CONTAINER TO SAID STORAGE VESSEL BY MEANS OF THE PRESSURE DROP IN THE SYSTEM CAUSING SAID VALVE TO OPEN AND SAID GAS UNDER PRESSURE TO FORCE SAID LIQUID INTO SAID STORAGE VESSEL THROUGH A SELECTED LINE, AND SAID THIRD LINE LEADING THE VAPORS GENERATED FROM SAID TRANSFERRED LIQUID IN THE STORAGE VESSEL TO THE PRESSURE SPACE IN ONE DIRECTION ONLY. 